Those who want you to doubt that anarchy (self ownership and individual responsibility) is the best, most moral, and ethical way to live among others are asking you to accept that theft, aggression, superstition, and slavery are perhaps better.

Well, the definition linked above says that back in the 1730s "legal tender" meant "currency that may be lawfully tendered in payment of a debt". Notice the word "may". Sounds nice and voluntary. I have no problem with that.

Unfortunately, the current definitions all include coercion: "Legally valid currency that may be offered in payment of a debt and that a creditor must accept" and "currency in specified denominations that a creditor must by law accept in redemption of a debt". Note the addition of the rude word "must".

I don't know about you, but my thinking has always been that if you feel the need to use coercion to get people to go along, your idea probably isn't a very good one.